Computerworld: Security has always been a big concern at data centers, but physical security at these facilities has become more of a concern since the 9/11 terrorist attacks ten years ago. For example, today's data centers are more likely to have crash-resistant fences and to use biometric ID systems.

In addition, 9/11 had a huge impact on the way companies approach site selection for data centers. Data centers are now much less likely to be in urban centers. In addition, backup and recovery centers now tend to be farther away from the main site--but not so far that staffers can't get there by car if air travel is shut down.